Field of the Invention
The present invention relates to an apparatus and a method for controlling the position of a control target using a disturbance estimation observer.
Description of the Related Art
There is a servo control system using an observer which servo-controls a control target and detects the absolute position of the control target to estimate a state amount such as position, speed, disturbance to be applied to the control target, or the like. Japanese Patent Laid-Open No. H4-238509 discloses a servo control system which is capable of directly and safely controlling a control target from any stopped position to a target position.
A control apparatus which is installed in a fixed coordinate system is assumed to be used in Japanese Patent Laid-Open No. H4-238509. If the installed attitude of the entire apparatus changes, a state amount is calculated based on a drive instruction applied to a drive unit but a drive instruction component for working against a change in attitude is biased, so that the result of the estimated state amount may be an erroneous estimated value.